The present invention is directed to an integrated circuit package and a method of making integrated circuit packages that are self-powered through the use of an integral solar cell.
As wafer technology has advanced, the size and power requirements of integrated circuit (IC) chips have decreased. For example, ball grid array (BGA) packages are widely used in mobile devices because they are very small and have low power requirements. However, the power supplied to the IC chip conventionally comes from an external power source, such as a battery. Thus, placement of the IC chip must always be carefully considered so that the IC chip can be adequately accessed for coupling with the external power source. This makes the embedding of IC chips in items such as clothes, shoes, bicycles, the human body, or the like very difficult.
At the same time, the efficiency of solar cells has continued to improve. Specifically, in optimum conditions, the light-receiving surface area of a solar cell that is required to generate power has decreased. It has been found that a solar cell sized at about the same order of magnitude as an IC chip can be efficient enough to meet the power demand of such IC chip in low power environments.
It is therefore desirable to provide an IC chip package that has an integral solar cell in order to reduce or eliminate the need for the IC chip to rely on an external power source.